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Taipei Takes Action against Flooding from Heavy Torrential Downpour
The Hydraulic Engineering Office (HEO) reported that the torrential rain on June 2 exceeded the rainfall standard for 200-year return period, resulting in flash floods at several areas across the city.According to the agency, the heaviest rainfall was reported in the vicinity around Donghu Elementary School in Neihu District, indicating rates up to 154 mm per hour.Unlike the standard operation procedures for flood gate activation during typhoons, the procedures taking effect during torrential rains do not require the agency to issue vehicle evacuation warnings 4-hours ahead of gate closure. The rain on June 2 led to rapid rise of water levels of the Keelung River near Dazhi Bridge, reaching alert levels by 12:40 PM. To ensure the safety of citizens, HEO issued notices regarding the closing of floodgates citywide at 1:30 PM. All of Taipei’s floodgates were closed by 2:30 PM. Regarding the flooding along Jiangnan Street in Neihu District, HEO pointed out that the primary causes were the low altitude of the neighborhood and the heavy downpour reaching 154 mm per hour. Furthermore, a temporary automatic pumping well which undergoes regular maintenance is located in the vicinity. Inspections during the storm of the facility indicated no system trouble.As for questions on the activation of water control outlets at Dahu Park, HEO explained that the water level of Dahu Lake is regulated by 20 storm water control outlets. Four of the sediment discharge gates were activated at 10 AM and deactivated at 3 PM when the downpour subsided. HEO reminds the public that all storm water drainage facilities have capacity limits. As Taipei’s drainage system is designed to relieve downpours of up to 78.8 mm per hour, torrential rains that exceed this amount can easily cause short term flooding. Such flooding will subside within a short period if the storm water drainage continues to function normally.